Silicone composition and process of making same

• US 20070106015A1
• Filed: 11/08/2005
• Published: 05/10/2007
• Est. Priority Date: 11/08/2005
• Status: Active Grant

• Current Assignee: Momentive Performance Materials Incorporated (Momentive Performance Materials Holdings LLC)
• Original Assignee: Momentive Performance Materials Incorporated (Momentive Performance Materials Holdings LLC)
• Inventors: Zhu, Aijun, Lamb, David
• Granted Patent: US 7,767,754 B2
• Time in Patent Office: Days
• US Class Current: 524/588
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/70 Siloxanes defined by use of the MDTQ nomenclature
• CPC Class Codes: C08G 77/80 Siloxanes having aromatic substituents, e.g. phenyl side groups
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

There is provided silicone gel-forming composition comprising a unique combination of polyorganosiloxane and organohydrogenpolysiloxane, which can produce silicone gel with improved hysteresis.

Claims

1. A curable hysteretic silicone gel-forming composition comprising:

(A) at least one organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule;

(B) at least one organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule, said organohydrogenpolysiloxane (B) being used in an amount such that the mole ratio of total amount of silicon-bonded hydrogen atoms contained in organohydrogenpolysiloxane (B) to one silicon-bonded alkenyl group contained in organopolysiloxane (A) is of from about 0.20 to about 0.79;

(C) filler in an amount of from about 25 to about 100 parts per hundred of organopolysiloxane(A);

(D) catalyst; and

,

(E) inhibitor;

wherein the recovery time of said curable hysteretic silicone gel-forming composition is greater than about 3 seconds.

2. The curable hysteretic silicone gel-forming composition of claim 1 where organopolysiloxane (A) comprises the reaction product of linear polyorganosiloxane, branched polyorganosiloxane, and three-dimensional network polyorganosiloxane.

3. The curable hysteretic silicone gel-forming composition of claim 1 where polyorganosiloxane (A) can further comprise, in addition to polyorganosiloxane that independently contain at least two silicon-bonded alkenyl groups per molecule;

non-alkenyl containing polyorganosiloxane selected from the group consisting of linear polyorganosiloxane, branched polyorganosiloxane, three-dimensional network polyorganosiloxane, resinous polyorganosiloxane and combinations thereof where each polyorganosiloxane does not contain any alkenyl groups.

4. The curable hysteretic silicone gel-forming composition of claim 1 where polyorganosiloxane (A) can be substantially resinous polyorganosiloxane and comprises, no less than about 30 weight percent of T and/or Q units, based upon the weight of substantially resinous polyorganosiloxane, where T=R⁶SiO_3/2 and Q=SiO_4/2, where R⁶ is selected from the group consisting of a monovalent hydrocarbon radical of from one to about sixty carbon atoms;

an unsaturated monovalent hydrocarbon radical containing from 2 to 10 carbon atoms; and

combinations thereof, provided that polyorganosiloxane (A) contains at least two silicon-bonded alkenyl groups per molecule.

5. The curable hysteretic silicone gel-forming composition of claim 1 where each organopolysiloxane (A) has a viscosity of from about 10 to about 1,000,000 centipoise at 25 degrees celsius and has the formula:

M_aM^vi_bD_cD^vi_dT_eT^vi_fQ_g

where

M=R⁷R⁸R⁹SiO_1/2;

M^vi=R¹⁰R¹¹R¹²SiO_1/2;

D=R¹³R¹⁴SiO_2/2;

D^vi=R¹⁵R¹⁶SiO_2/2;

T=R¹⁷SiO_3/2;

T^vi=R¹⁸SiO_3/2; and

Q=SiO_4/2

where R⁷, R⁸, R⁹, R¹³, R¹⁴ and R¹⁷ are independently monovalent hydrocarbon radicals having from one to sixty carbon atoms;

R¹⁰ is a monovalent unsaturated hydrocarbon radical having from two to ten carbon atoms, and R¹¹ and R¹² are independently monovalent hydrocarbon radicals having from one to sixty carbon atoms;

R¹⁵ is a monovalent unsaturated hydrocarbon radical having from two to ten carbon atoms, and R¹⁶ is a monovalent hydrocarbon radical having from one to sixty carbon atoms;

R¹⁷ is a monovalent unsaturated hydrocarbon radical having from two to ten carbon atoms;

the stoichiometric subscripts a, b, c, d, e, f, and g are either zero or positive subject to the following limitations;

c is greater than 10;

d is from zero to about 40;

when d=0, b=2;

b is from zero to two provided that when b=0, d=2;

b+d is of from 2 to about 40, when b=1, a=1;

a+b>

2; and

in a substantially straight chain organopolysiloxane if e+f+g>

0, then a+b+c+d>

e+f+g; and

organopolysiloxane (A) contains at least two silicon-bonded alkenyl groups per molecule.

6. The curable hysteretic silicone gel-forming composition of claim 1 where at least two silicon-bonded alkenyl groups contain from 1 to about 6 carbon atoms.

7. The curable hysteretic silicone gel-forming composition of claim 1 where at least two silicon-bonded alkenyl groups are vinyl.

8. The curable hysteretic silicone gel-forming composition of claim 1 where organo groups of organopolysiloxane (A) comprise methyl and/or phenyl.

9. The curable hysteretic silicone gel-forming composition of claim 1 where organohydrogenpolysiloxane (B) comprises the reaction product of linear organohydrogenpolysiloxane, branched organohydrogenpolysiloxane, cyclic organohydrogenpolysiloxane and three-dimensional network organohydrogenpolysiloxane.

10. The curable hysteretic silicone gel-forming composition of claim 1 where organohydrogenpolysiloxane (B) can further comprise, in addition to organohydrogenpolysiloxane (B) that independently contain at least two silicon-bonded hydrogen atoms per molecule;

non-hydrogen containing organohydrogenpolysiloxane selected from the group consisting of linear organohydrogenpolysiloxane, branched organohydrogenpolysiloxane, cyclic organohydrogenpolysiloxane, three-dimensional network organohydrogenpolysiloxane, resinous organohydrogenpolysiloxane and combinations thereof where each organohydrogenpolysiloxane does not contain any silicon-bonded hydrogen atoms.

11. The curable hysteretic silicone gel-forming composition of claim 1 where organohydrogenpolysiloxane (B) is substantially resinous organohydrogenpolysiloxane and comprises no less than about 30 weight percent of T and/or Q units, where T=R²⁴SiO_3/2 and Q=SiO_4/2, where R²⁴ is selected from the group consisting of a monovalent hydrocarbon radical of from one to about sixty carbon atoms;

a hydrogen atom; and

combinations thereof.

12. The curable hysteretic silicone gel-forming composition of claim 1 where organohydrogenpolysiloxane (B) has the formula:

M_hM^H_iD_jD^H_kT_LT^H_mQ_n

where

M=R²⁷R⁷R²⁹SiO_1/2;

M^H=R³⁰R³¹HSiO_1/2;

D=R³²R³³SiO_2/2;

D^H=R⁴ HSiO_2/2;

T=R³⁵SiO_3,2;

T=HSiO_3/2; and

Q=SiO_4/2;

where R²⁷,R²⁸, R²⁹, R³², R³³, and R³⁵ are independently monovalent hydrocarbon radicals having from one to sixty carbon atoms and are substantially free of aliphatic unsaturation;

R³⁰, R³¹, and R³⁴ are independently monovalent hydrocarbon radicals having from one to sixty carbon atoms or hydrogen and are substantially free of aliphatic unsaturation the stoichiometric subscripts h, i, j, k, L, m and n being zero or positive subject to the following limitations;

J is greater than 0;

k is of from zero to about 20, when k=0, i=2;

h is of from zero to about 2;

subject to the further limitation that i+k is of from 2 to about 20, when i=1, h=1;

h+i>

2; and

in at least one substantially straight chain organohydrogenpolysiloxane if L+m+n>

0 then h+i+j+k>

L+m+n; and

organohydrogenpolysiloxane (B) contains at least two silicon-bonded hydrogen atoms per molecule.

13. The curable hysteretic silicone gel-forming composition of claim 1 where each organohydrogenpolysiloxane (B) has a viscosity of from about 0.1 to about 2000 centipoise at 25 degrees celsius.

14. The curable hysteretic silicone gel-forming composition of claim 1 where each organohydrogenpolysiloxane (B) has a viscosity of from about 0.5 to about 1000 centipoises at 25 degrees celsius.

15. The curable hysteretic silicone gel-forming composition of claim 1 where each organohydrogenpolysiloxane (B) has a viscosity of from about 1 to about 500 centipoise at 25 degrees celsius.

16. The curable hysteretic silicone gel-forming composition of claim 1 where the mole ratio of total amount of silicon-bonded hydrogen atoms contained in organohydrogenpolysiloxane (B) to one silicon-bonded alkenyl group contained in organopolysiloxane (A) is of from about 0.25 to about 0.75.

17. The curable hysteretic silicone gel-forming composition of claim 1 where the mole ratio of total amount of silicon-bonded hydrogen atoms contained in organohydrogenpolysiloxane (B) to one silicon-bonded alkenyl group contained in organopolysiloxane (A) is of from about 0.30 to about 0.65.

18. The curable hysteretic silicone gel-forming composition of claim 1 where filler (C) is present in an amount of from about 35 to about 80 parts by weight per 100 parts of organopolysiloxane (A).

19. The curable hysteretic silicone gel-forming composition of claim 1 where filler (C) is present in an amount of from about 40 to about 65 parts by weight per 100 parts of organopolysiloxane (A).

20. The curable hysteretic silicone gel-forming composition of claim 1 where filler is selected from the group consisting of silica, fumed silica, precipitated silica, titania, alumina, clay, wollastonite, quartz and combinations thereof.

21. The curable hysteretic silicone gel-forming composition of claim 1 where catalyst (D) is at least one Group VIIIB catalyst.

22. The curable hysteretic silicone gel-forming composition of claim 1 where inhibitor (E) has aliphatic unsaturation and is selected from the group consisting of diallyl maleate, D-4 vinyl, 2-methyl-3-butene-2-ol, 1-ethynyl-1-cyclohexanol, 3,5,-dimethyl-1-hexyn-3-ol and combinations thereof.

23. The curable hysteretic silicone gel-forming composition of claim 1 comprising the specific formulation where organopolysiloxane (A) is a combination of (A-i) vinyl organopolysiloxane having a viscosity of from about 20,000 to about 60,000 centipoise at 25 degrees celsius, being present in an amount of from about 60 to about 75 weight percent, and (A-ii) vinyl organopolysiloxane having a viscosity of from about 250 to about 750 centipoise at 25 degrees celsius being present in an amount of from about 5 to 15 about weight percent;

organohydrogenpolysiloxane (B) is at least one organohydrogenpolysiloxane that has terminal group silicon-bonded hydrogen atom and/or additional silicon-bonded hydrogen atom beyond terminal group silicon-bonded hydrogen atom per molecule and having a viscosity of from about 15 to about 60 centipoise at 25 degrees celsius, being present in an amount of from about 0.2 to about 0.5 weight percent;

filler (C) being fumed silica with a surface area of from about 200 to about 350 m²/g, said fumed silica having been treated with silane, where filler (C) is present in an amount of from about 15 to about 25 weight percent;

catalyst (D) is a platinum catalyst where catalyst (D) is present in an amount of from about 10 to about 20 parts per million; and

, inhibitor (E) is 1-ethynyl-1-cyclohexanol where inhibitor (E) is present in an amount of from about 0.05 to about 0.1 weight percent, with all weight percents being based upon the total weight of the curable hysteretic silicone gel-forming composition.

24. A hysteretic silicone gel obtained from the curing of curable hysteretic silicone gel-forming composition of claim 1.

25. The hysteretic gel of claim 24 having a recovery time of specifically greater than about 3 seconds.

26. A hand-grippable device having an external surface at least a portion of which comprises hysteretic silicone gel of claim 25.

27. The hand-grippable device of claim 26 which is a writing implement, a razor, a toothbrush, a utensil, sport equipment, a tool, a motor-driven device, or a steering wheel.